Your company, GymGrub, wants to collect big data to understand what gym-goers prefer to eat for post-workout meals. Which approach would be most effective for gathering this type of big data?
1) By analyzing sales data of post-workout meals and shakes from the gym's café
2) By conducting interviews with a handful of regular gym members
3) By consulting with gym trainers about what they believe their clients prefer to eat
4) By surveying as many people as possible who walk past the gym